The non-coding RNA OTUB1-isoform2 promotes ovarian tumour progression and predicts poor prognosis.

Ovarian cancer is the leading malignancy of the female reproductive system and is associated with inconspicuous early invasion and metastasis. We have previously reported that the oncogene OTUB1 plays a crucial role in ovarian cancer progression, but the role of its isoform, the non-coding RNA OTUB1-isoform2, in ovarian cancer is still elusive. Here, we reported that OTUB1-isoform2 expression in ovarian cancer tissues was significantly higher than that in the paired paratumorous tissues (P < .01). The patients with high expression of OTUB1-isoform2 had larger tumours than those with low expression (P < .05). The high expression of OTUB1-isoform2 was correlated with the involvement of bilateral ovaries (P < .05), lymph node metastasis (P < .05), vascular invasion (P < .05), greater omentum involvement (P < .01), fallopian tube involvement (P < .05), advanced FIGO stages (P < .01) and recurrence (P < .01). Moreover, OTUB1-isoform2 served as an independent negative prognostic predictor for disease-free survival (DFS) and disease-specific survival (DSS). Overexpression of OTUB1-isoform2 in the ovarian cancer cells stimulated cell proliferation, migration and invasion both in vitro and in vivo. In summary, our study suggested that OTUB1-isoform2 is a novel prognostic biomarker with independent oncogenic functions for ovarian cancer.